1. Technical Field of the Invention
The present invention relates to communication systems, and more particularly to methods and arrangements incorporating packet-switched technologies into communications networks having time-critical radio interfaced communication nodes.
2. Description of Related Art
Traditional circuit-switched technologies require dedicated network resources. To the contrary, packet-switched technologies allow shared use of precious network resources, such as, for example, the communication links between network nodes. As such, the use of packet-switched communication technologies within communications networks tends to promote optimal use and improved efficiency of selected network resources. For this reason, there is a continuing drive within the telecommunications industry to integrate packet-switched technologies into existing communications networks in a manner that does not significantly degrade the quality of service provided to the network users or subscribers. In mobile telecommunications networks, for example, the use of a packet-switched network that is not well designed and dimensioned may potentially introduce an increased delay over traditional circuit-switched networks.
Consequently, there is a need to identify portions of existing communications networks that can benefit from packet-switched technologies without significantly diminishing the quality of service provided to the subscribers.
In accordance with certain aspects of the present invention, portions of a communications network that can be optimized by integrating packet-switched technologies have been identified. These portions include a transport network, for example, as found between a time-critical radio interface node and a switching node and/or a gateway node. In the past, transport networks have used circuit-switched technologies to provide dedicated communications resources between the two nodes. Such dedicated communications resources add significantly predictable and measurable delays to the communicated data. As such, the time-critical radio interface node is typically arranged to provide radio interface timing data to the switching node to further optimize processing and/or reduce communication related delays.
Circuit-switched technologies have the additional benefit that they can allow for transcoded data to be sent from the switching node to the radio interface node in very small increments (i.e., a couple of bits of transcoded data at a time), even before the entire transcoding operation is completed. Unfortunately, such circuit-switched transport networks and associated arrangements tend to require the availability of dedicated resources allocated according to the peak usage.
Introduction of more cost-effective, packet-switched technologies will significantly reduce the communication resource requirements. However, packet-switched technologies tend to be less predictable with regard to delays and require that larger packets of data be processed at a time by the switching node or gateway node. Consequently, many of the contemporary optimization solutions employed in existing circuit-switched transport networks and associated arrangements will need to be modified in order for packet-switched technologies to maintain the quality of service expected by subscribers.
The present invention provides methods and arrangements that can be used to integrate packet-switched technologies into communications networks and/or optimize the use of the packet-switched technologies to provide time-critical data between at least two nodes of a communications network.
The above stated needs and others are met, in accordance with certain embodiments of the present invention, by an arrangement for use in a communications network having at least one radio interface. The arrangement includes a transport network that is configured to carry packets containing coded data. A first node is connected to the transport network. The first node is configured to send and receive radio signals over a radio interface. The first node also outputs radio signal timing parameters associated with the radio signals.
At least a second node is connected also to the transport network. The second node includes a plurality of transcoders and at least one controller. Each of the plurality of transcoders is selectively configurable to convert between a first data format and a second data format, wherein the second data format includes coded data, for example compressed voice data.
The controller is configured to receive the radio signal timing parameters as carried over the transport network. The controller determines at least one desired coded data timing parameter based on the received radio signal timing parameters, and selects at least one of the transcoders to convert between the first data format and the second data format in support of a call.
The transcoder is preferably selected based on its availability to provide the coded data to the first node in significant accordance with the desired coded data timing parameter.
In certain further embodiments, each of the transcoders is configured to output corresponding current status information to the controller identifying the availability of the transcoder to support the call.
Furthermore, the transcoders in certain embodiments are configured to recursively process a plurality of concurrent calls by assigning each of the concurrent calls to at least one predefined processing period selected from a group of predefined processing periods. Thus, for example, the current status information for these transcoders could identify the unused processing periods.
In accordance with still further embodiments of the present invention, the first and second nodes in the above arrangement are part of a Global System for Mobile (GSM), wherein the first node includes a base transceiver station and the second node includes a base station controller, and/or a mobile switching center, and/or a gateway mobile switching center. Such an arrangement can be used to provide full-rate GSM calls, for example, between a mobile station and at least one non-GSM telecommunications terminal.
In accordance with other embodiments of the present invention, the above-stated needs and others are also met by arrangement for use in a communications network having a transport network that is configured to carry packets containing coded data. Here, the arrangement is operatively connectable to the transport network and includes a plurality of transcoders and at least one controller connected thereto. Each of the transcoders is selectively configurable to convert between a first data format and a second data format, wherein the second data format includes coded data. The controller is configured to receive radio signal timing parameters, determine at least one desired coded data timing parameter, and select at least one transcoder from among the plurality of transcoders to convert between the first data format and the second data format in support of a call based on the availability of the selected transcoder to provide the coded data in significant accordance with the desired coded data timing parameter. To support this selection process, each of the plurality of transcoders is configured to output current status information to the controller, wherein the current status information identifies the availability of the transcoder to support the call.
A method for use in a communications network having at least one radio interface is also provided, in accordance with certain embodiments of the present invention. The method includes the steps of arranging a transport network to carry packets containing coded data between a first node and a second node, using the first node to send and receive radio signals over a radio interface, and determining radio signal timing parameters associated with the radio signals. The method further includes the steps of providing a plurality of transcoders, each of which is selectively configurable to convert between a first data format and a second data format, the second data format containing the coded data, and using at least one controller to receive the radio signal timing parameters, determine at least one corresponding desired coded data timing parameter, and select at least one of the transcoders to convert between the first data format and the second data format in support of a call based on the availability of the selected transcoder to provide the coded data in significant accordance with the desired coded data timing parameter. In certain embodiments, the method also includes the step of causing each of the plurality of transcoders to output current status information to the controller, wherein the current status information identifies the availability of the transcoder to support the call.